How to install gary adapter chip mod in A500 with A500+ board

edge-records · 26 February 2019, 00:25

Hello Amigos

I'm stuck: I've bought a 2mb ram expansion from boobip.com with a Gary adapter, but the described instructions don't fit my board.

I've got a rev 8a rev A500+ board, but it is a simple A500 with 512KB RAM.

There are 2 installation options described:
http://www.boobip.com/hardware/A500_...-_chip_RAM_mod for 500+

http://www.boobip.com/hardware/A500_...0_chip_RAM_mod for 500

But I can't really follow either. My board doesn't have a chip at U32 like in the A500+ pics, and my J2 is at a different location than in the A500 pics. I've tried to find instructions in this forum but couldn't find any.

Can anyone shed some light in how I can get it upgraded?

Thanks in advance!!!
Stephan

solidcore · 26 February 2019, 03:00

Stephan,

I too have same board , it is a nice board

good find! not made it into a real a500+ yet, the issue is we need to populate the board and set the solder jumpers according to the real a500+ , this requires some searching around for parts, check out the a500+ schematics pdf and close inspect boards. Try amiga pcb explorer, that helps a lot. Hope to see how you progress.

cmorley · 26 February 2019, 11:46

Hi Stephan,

If it is an 8A but with only 512K then follow the A500 instructions. JP2 is in a slightly different place on all the models (3, 5, 6A, 8A) but the function is identical.

You can email me directly if you need more help.

Chris

Edit: If you want to upgrade to a full A500+ first then http://eab.abime.net/showthread.php?t=77705.

edge-records · 26 February 2019, 13:32

Thanks Chris, will follow the A500 instructions then!

I would never want to upgrade the A500 to a A500+ with my 8a board. Consider me naive, but I see myself more like a custodian of these machines than like an owner, so I want to keep them as much as possible in their original condition. Adding a cable to an empty soldering point, or swapping broken parts, or parts that endanger the board is one thing, but cutting tracks like for the A500+ instructions I consider an absolute No-no. It seems to be very frowned upon by today's Amiga enthusiasts to have a hole with a switch in the side of the A500, but people are ready to cut wires on the board, and solder in new LEDs and what not. In my view that is misguided and the wrong way around. My first Amiga 500 I bought used from a friend in in 1991 or so already had a switch in the side of the case to switch memory types, so this is a much more authentic and time-historical mod you would find in a good museum in 100 years, than a cut wire on the logic board, with anachronistic chips on the board.

In fact I would even go as far as saying that people who do this, making a 500+ out of their 8a 500 do this more for their own enjoyment and the challenge of it, and not out of appreciation of their machines. I think they destroy them in the process to be usable as a contemporary document.

cmorley · 26 February 2019, 15:14

I understand your point of view. My rev 3 A500 is totally original

You can do the A500+ mod for my RAM with lifting a pin instead of cutting a track so it is reversible.

jbilander · 10 April 2019, 17:14

Quote:

Originally Posted by cmorley

You can do the A500+ mod for my RAM with lifting a pin instead of cutting a track so it is reversible.

Hi, Chris

Just to be clear, does that mean lifting pin 2 on U34 and wire it to your expansion memory card just like in your picture (purple wire) and not cutting the trace on mobo? I know this is for rev8a board, so not for me with 6a, but I was just curious

That would be a cleaner reversible mod if you have a proper de-soldering station (with vacuum pump) that can free that pin from tin and then you just lift it up carefully with a plier so it "flies in the air". You could also use mini-clips for the two wires U32 and U34 so no soldering required.

cmorley · 10 April 2019, 18:18

Yes exactly as you explain jbilander.

Lifting that pin is not easy not least because the SIP resistor pack is mm away but it can be done with the correct tools and skill.

Pin might snap if you bend it back to undo the mod but U34 is only a common 74 chip so can easily be replaced with new.

jbilander · 10 April 2019, 19:24

Nice, thanks for the info. I like that mod

Good to know if I ever get my hands on a rev 8a board...

26 February 2019, 00:25	#1
edge-records Registered User Join Date: Feb 2019 Location: UK Posts: 7	How to install gary adapter chip mod in A500 with A500+ board Hello Amigos I'm stuck: I've bought a 2mb ram expansion from boobip.com with a Gary adapter, but the described instructions don't fit my board. I've got a rev 8a rev A500+ board, but it is a simple A500 with 512KB RAM. There are 2 installation options described: http://www.boobip.com/hardware/A500_...-_chip_RAM_mod for 500+ http://www.boobip.com/hardware/A500_...0_chip_RAM_mod for 500 But I can't really follow either. My board doesn't have a chip at U32 like in the A500+ pics, and my J2 is at a different location than in the A500 pics. I've tried to find instructions in this forum but couldn't find any. Can anyone shed some light in how I can get it upgraded? Thanks in advance!!! Stephan

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26 February 2019, 03:00	#2
solidcore Registered User Join Date: Sep 2017 Location: birmingham, uk Posts: 548	Stephan, I too have same board , it is a nice board good find! not made it into a real a500+ yet, the issue is we need to populate the board and set the solder jumpers according to the real a500+ , this requires some searching around for parts, check out the a500+ schematics pdf and close inspect boards. Try amiga pcb explorer, that helps a lot. Hope to see how you progress.

26 February 2019, 11:46	#3
cmorley Registered User Join Date: Jun 2018 Location: Oxford, UK Posts: 66	Hi Stephan, If it is an 8A but with only 512K then follow the A500 instructions. JP2 is in a slightly different place on all the models (3, 5, 6A, 8A) but the function is identical. You can email me directly if you need more help. Chris Edit: If you want to upgrade to a full A500+ first then http://eab.abime.net/showthread.php?t=77705.

26 February 2019, 13:32	#4
edge-records Registered User Join Date: Feb 2019 Location: UK Posts: 7	Thanks Chris, will follow the A500 instructions then! I would never want to upgrade the A500 to a A500+ with my 8a board. Consider me naive, but I see myself more like a custodian of these machines than like an owner, so I want to keep them as much as possible in their original condition. Adding a cable to an empty soldering point, or swapping broken parts, or parts that endanger the board is one thing, but cutting tracks like for the A500+ instructions I consider an absolute No-no. It seems to be very frowned upon by today's Amiga enthusiasts to have a hole with a switch in the side of the A500, but people are ready to cut wires on the board, and solder in new LEDs and what not. In my view that is misguided and the wrong way around. My first Amiga 500 I bought used from a friend in in 1991 or so already had a switch in the side of the case to switch memory types, so this is a much more authentic and time-historical mod you would find in a good museum in 100 years, than a cut wire on the logic board, with anachronistic chips on the board. In fact I would even go as far as saying that people who do this, making a 500+ out of their 8a 500 do this more for their own enjoyment and the challenge of it, and not out of appreciation of their machines. I think they destroy them in the process to be usable as a contemporary document.

26 February 2019, 15:14	#5
cmorley Registered User Join Date: Jun 2018 Location: Oxford, UK Posts: 66	I understand your point of view. My rev 3 A500 is totally original You can do the A500+ mod for my RAM with lifting a pin instead of cutting a track so it is reversible.

10 April 2019, 18:18	#7
cmorley Registered User Join Date: Jun 2018 Location: Oxford, UK Posts: 66	Yes exactly as you explain jbilander. Lifting that pin is not easy not least because the SIP resistor pack is mm away but it can be done with the correct tools and skill. Pin might snap if you bend it back to undo the mod but U34 is only a common 74 chip so can easily be replaced with new.

10 April 2019, 19:24	#8
jbilander Registered User Join Date: Jun 2018 Location: Stockholm Age: 48 Posts: 271	Nice, thanks for the info. I like that mod Good to know if I ever get my hands on a rev 8a board...

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